TRENDnet TK-408K 4-Port PS/2 Audio KVM Switch - 4 x 1 - 4 x D-Sub (HD-15) Keyboard/Mouse/VGA - KVM Switch $49.99

The TK-408K 4-Port PS/2 Audio KVM Switch lets you control multimedia PCs with just one keyboard, monitor, mouse, microphone, and a set of speakers. The KVM switch not only allows you to share your monitor, keyboard and mouse but you can also share microphone and speakers. With just a simple press of a button, this KVM switch eliminates the hassle of cable swapping and switching between 4 PCs. With it's Hot-Plug, Auto-Scan and Hot-Key operating features, the TK-408K is the perfect choice for managing 4 PCs.

Buy.com is carrying this 4-Port PS/2 Audio KVM Switch for $49.99